Rotating heat exchanger



Dec. 6, 1960 J. GASSMANN ETAL 2,963,278

ROTATING HEAT EXCHANGER 1 Filed July 5, 1957 2 Sheets-Sheet 1 INVENTORS JOHAN NES GLASSMAN HORST WITT ATTORNEY 3 Dec. 6, 1960 J. GASSMANN ETIAL 2,963,278

ROTATING HEAT EXCHANGER Filed July 5, 1957 2 Sheets-Sheet 2 3 4 V/m sl INVENTORS JOHANNES GASSMAN HORST WITT BY nd ATTORNEYS States ROTATING HEAT EXCHANGER Johannes Gassmann, Altbach, near Esslingen, and Horst Witt, Stuttgart, Germany, assignors to Daimier-Benz Aktiengesellschaft, Stuttgart, Unterturkheini, Germany The present invention relates to a rotating heat exchanger, and more particularly to a rotating heat exchanger of drum-like construction provided with stationary connections for the inlet and outlet of the air or gas and with a rotary heat exchanger formed by lamellae or disks which is traversed in a first sector of the heat exchanger portion by the gas flowing therethrough and in the remaining sector thereof by the air flowing therethrough.

The present invention is primarily intended for use of heating the combustion air for motor-vehicle and stationary gas-turbines.

In the known heat exchangers of the prior art which were provided with annularly-shaped stacks of lamellae or disks, the disks or lamellae became dirty oftentimes after a short period of operation thereof which resulted in a reduction of the exchange of heat therein so as to make necessary repeated exchange and cleaning of the stacks of disks. However, an interruption of the operating or working time of the gas turbine was accompanied every time with each exchange or cleaning of the disks which had a disadvantageous effect on the overall efficiency and economy of the particular installation.

Accordingly, it is an object of the present invention to provide a heat exchanger which automatically prevents dirt or other foreign particles from collecting at the disks or being deposited thereat to avoid any reduction of the capacity thereof to transfer or exchange heat between the two fluid media.

It is another object of the present invention to provide a particular simple and effective construction of the seals between the two compartments for the two gases or fluid media which seals are simultaneously effective to wipe off and clean the disks.

It is another object of the present invention to reduce or minimize the down-time of the gas turbine, the combustion air of which is heated in the heat exchanger, by reason of minimizing the necessity for disassembling the heat exchanger to clean the annularly-shaped lamellae thereof.

Another object of the present invention resides in the provision of a spacing and cleaning arrangement installed in operative relationship with the lamellae or disk of the heat exchanger which increases the overall economy and efficiency of the entire installation.

These and other objects of the present invention will become more clear from the following description when taken in connection with the accompanying drawing which shows, for purposes of illustration only, one preferred embodiment in accordance with the present invention, and wherein:

Figure l is an axial cross-sectional-viewof a rotary, self cleaning heat exchanger in accordance with the present invention;

Figure 2 is a front view of the heat exchanger shown in Figure 1 as seen in the direction of the axis of rotation 2,953,278 Patented Dec. 6, 1960 thereof with certain parts thereof broken away for sake of clarity, and

Figure 3 is an enlarged partial cross-sectional view taken along line 3-3 of Figure 2.

The present invention consists essentially in that sheetmetal strips or the like of suitable configuration are arranged between the annularly-shaped disks or lamellae of the heat exchanger which strips maintain the disks at a predetermined distance from one another and also wipe ofi any foreign particles which may have collected at the disks. At the same time, the sheet metal strips may also function at the separating joints as seals between the two gas streams or fluid media.

In accordance with a further feature of the present in vention, the sheet-metal strips may be combined into combs provided with a plurality of teeth as viewed in the longitudinal cross section thereof, whereby the teeth are preferably provided with side surfaces extending conically toward each other so that in the direction of rotation the width thereof decreases. As a result of such a construction, the edges formed by the intersection of the conical side walls and the widest transverse wall of each tooth are disposed opposite to and thereby encounter first the disk portions arriving at the sheet-metal strips in the direction of rotation thereof and, therefore, wipe off any dirt or foreign particles which may have collected thereon. It is essential in connection therewith that not only a clogging up of the heat exchanger but also a slight deposit of dirt at the disks is avoided which in certain cases might considerably reduce the heat transfer and therewith the efiiciency of the heat exchanger.

if the sheet-metal strips are combined at the lower end thereof into a comb-like structure, then it is possible to secure the same thereat in a particularly simple manner. Preferably, for purposes of securing a row of sheet-metal strips in the heat exchanger a place located within the annularly-shaped disks is selected. The combs formed by the sheet-metal strips may also be secured in the circumferential direction thereof in an inclined manner, and more particularly in such a manner that an edge of the sheet-metal strip first intersects a radius of the annular disk at the side thereof closer to the center and only thereafter on the outer side thereof, i.e., in such a manner that the leading edge of the strip is inclined upwardly and rearwardly in the direction of rotation of the disks.

Referring now to the drawing, wherein like reference numerals are used throughout the various views to designate like parts, the reference numeral 1 designates a round housing in which the heat exchanger is accommodated. Starting with the center point of the housing 1, as viewed in Figure 2, the heat exchanger is subdivided into three concentric sections. The inlet or discharge of the air and gas takes place in the inner disk-shaped section 2. An annularly-shaped center section, constituting the heat ex? change section 3, properly speaking, adjoins the center section 2 outwardly thereof, and another annularly-shaped outer section 4, forming the annular air and gas channels follows the center section 3radially outwardly thereof.

The inner section 2 is subdivided by the separating .wall portions 5, 6, '7 and 8 essentially into two sectors which together with the other housing wall'parts 9 and it), which in turn enclose the-inner section 2, form the connections for the admission or discharge of the air and gas. For example, air enters into the interior of the heat exchanger through the channel 11 in the direction of the arrow 11 (Figure 1), and traverses that portion of the heat xchanger section 3 in the direction of arrow C which lies within the annular sector 12 and which is defined "b'ythe sheet-metal strips forming the sealing boundary walls and 14 thereof in the circumferential direction. After passage through the heat exchanger part 3,'"and more pa ticularly after passage through the annular sector 12hr the heat exchanger part 3 properly speaking, the air arrives in the outer annular sector which is in communication with the air discharge channel 16 and the air discharge connecting member 17 through which heated air is then conducted away.

In the illustrated embodiment, the gas serving for purposes of heating traverses the heat exchanger in the counterflow principle, i.e., the gas flows in the opposite direction as the air through the stack of lamellae or disks. Consequently, the gas serving as heating medium enters over the connecting member 18 through the channel 19 into the outer annular sector 20, flows from there in the direction of arrow B over the annular sector 21 intended for the gas which is limited by the boundary walls 13 and 14, through the stack of disks disposed therein, and is thereupon collected in the sector space 22 formed by a part of the inner section 2 and is discharged therefrom through the funnel-shaped sector defined by walls 5, 6 and 8. It should also be noted that the concentrically disposed two inner sections 2 and 3 of the heat exchanger are arranged eccentrically to the outermost section 4 thereof so that from the end formed by the transversely extending separating wall portion 14 to the air connecting member 17 or gas connecting member 18, respectively, i.e., approximately to the separating wall portion 13, increasingly larger annular channels are formed, i.e., channels 15 and of increasingly larger cross section are provided.

The exchange or transfer of heat between gas and air takes place upon rotation of the stack of disks. The stack of individual annular disks or lamellae 28 is retained between rigidly or springily supported rollers 24 mounted on shafts 23 of which at least one is driven from any suitable'external source (not shown) such as from an electric motor or the like. In the illustrated embodiment, the roller 24 is provided with external gear teeth 25 which mesh with the external gear teeth 26 of the outer disk ring 27.

The individual disks 28 are connected with the disk ring 27, for example, by means of transversely extending spacer bars or support elements 41 disposed at an acute angle to the axis of rotation of the disks. The spacer bars 41 are provided with appropriate grooves to accommodate therein the indvidual disks 28. The spacer bars or support elements 41 are suitably supported and secured on one side thereof in thedisk ring 27. The other side of the spacer bars 41 may also be suitably supported and secured in any appropriate manner, for example, in a ring similar to ring 27 which is disposed on the opposite side of the heat exchanger.

If the disk ring 27 together with the individual disks 28 are set into rotation in the direction of arrow A by rotating roll 24 then the individual disks 28 continuously receive or absorb heat from the gases flowing therethrough within the sector 21 defined by the boundary wall 13 to the boundary wall portion 14. Beginning with the boundary Wall 14 to the boundary wall 13 the stack of disks 28 then give up again the heat absorbed from the gas to the air flowing from space 11 over the annular sector 12 in the direction of arrow C toward the outer annular sector 15.

Foreign bodies as well as dirt particles and other impurities, primarily taken along by the combustion gases but also by the unfiltered air deposit themselves readily at the disks 28 which themselves are relatively thin, for example, 0.10 mm. in thickness, and which are spaced from one another only at a very slight distance, for example, at a distance of 0.25 mm., andthereby clog up the same or at least contribute considerably to the reduction of the transfer of heat. In order to avoid deposition of these foreign particles, sheet-metal strips 29 are arranged between the individual disks 28 which strips also form the separating walls 13 and 14. As best shown in Figure 3, the sheet-metal strips 29 are of decreasing width in the direction of rotation, i.e., have a wedgeshaped cross section as viewed in Figure 3, so that each time the edge 30 (Figure 2) which is first touched by the disks 28 in the direction of rotation thereof offers a larger cross section than the rear edge 31 thereof. The edges formed by the intersection of the side surfaces of the sheet-metal strips 29 and of the surfaces 30, therefore, produce a wiping action along the annular disk surfaces and thereby continuously clean the same.

The individual sheet-metal strips 29 are combined in a comb-like manner in the respective base portions thereof disposed toward the center in a manner not indicated in detail and are connected with the base portion 32 of the comb in any suitable manner. The base portion 32 of the comb-like assembly is held together in any suitable manner, for example, by means of the bolts or the like also used to hold the same in assembled position in the heat exchanger. The inclined arrangement of the sheet-metal strips 29, whereby the strips 29 are arranged slightly slantingly with the outer ends thereof in relation to the inner ends thereof in the direction of rotation, is particularly advantageous for purposes of cleaning. As a result of such an inclined arrangement, the inner parts of the disk stack disposed in a given radial plane, therefore, reach or encounter earlier the sheet-metal strip comb than the outer parts thereof which are disposedin the same radial plane. Such an arrangement is particularly advantageous for the removal of foreign particles.

While we have shown and described one preferred embodiment in accordance with the present invention, it is understood that the same is not limited thereto but is susceptible of many changes and modifications within the spirit of the present invention, and we intend to cover all such changes and modifications as encompassed by the appended claims.

We claim:

1. A rotating heat exchanger. for transferring heat from a first fluid medium to a second fluidmedium comprising rotary heat exchange means formed by a plurality of annularly-shaped rotatable disks provided with a central opening, means including said central opening and said disks for forming a first sector for the passage therethrough in a radial direction of one of said fluid media and for forming a second sector for the passage therethrough in a radial direction of the other of said fluid media to transfer heat to said other medium from said one medium by said disks, and spacing means located between said disks for simultaneously spacing said disks and continuously wiping off foreign particles deposited at said disks.

2. A rotating heat exchanger according to claim 1, further comprising stationary inlet and outlet connections for said media, said stationary inlet and outlet connections being in communication with a respective one of said passages.

3. A rotating heat exchanger for transferring heat from a first fluid medium to a second fluid medium comprising a cylindrical casing, rotary heat exchange means formed by a plurality of rotatable annularly-shaped disks having a central opening therein and disposed eccentrically within said casing to thereby form difiuser-like inlet and outlet annuli between the periphery of said disks and said cylindrical casing, means including said central opening and said disks for forming a first sector for the passage therethrough in an essentially radial direction of one of said fluid media and for forming a second sector for the passage therethrough in an essentially radial direction of the other of said fluid media to transfer heat to said other medium from said one medium by said disks, and means located between said disks and including a plurality of sheet-metal strips for simultaneously spacing said disks and continuously wiping off foreign particles deposited at said disks.

4. A rotating heat exchanger according to claim 3, wherein said sheet-metal strips are combined into a comblike assembly at the base portions thereof provided with a plurality of teeth formed by said strips.

5. A rotating heat exchanger according to claim 3, wherein said sheet-metal strips are essentially wedgeshaped in cross section with the apex thereof disposed in the direction of rotation of said disks in relation to the base thereof, so that the edges formed by the intersections of the base surface and side surfaces of the comb wipe off any foreign particles at said disks.

6. A rotating heat exchanger according to claim 3, wherein said sheet-metal strips assume the function of seals between said two media and define a boundary between said two sectors.

7. A rotary heat exchanger of drum-shaped construction for heating the combustion air of a gas turbine by heated gases comprising stationary inlet and discharge means for said air and gas, rotary heat exchange means formed by a plurality of annularly-shaped rotatable disks provided with a central opening therein, passage means in said heat exchanger including said central opening subdividing the same and forming a first sector traversed by said gas and another sector traversed by said air for transferring heat to said combustion air of said gas turbine from said gas by said disks, and means including a plurality of wedge-shaped sheet-metal strips disposed between said annularly-shaped disks extending outwardly and inclined with respect to said radial direction for simultaneously maintaining said disks at a predetermined distance and continuously wiping off foreign particles deposited thereat.

8. A rotary heat exchanger of drum-shaped construction according to claim 7, wherein said sheet-metal strips also form the seals for defining the boundary between said two sectors.

9. A rotary heat exchanger according to claim 7, wherein said sheet-metal strips are essentially wedgeshaped in cross section to provide a base surface and two side surfaces slanting towards each other in the direction of rotation of said disks.

10. A rotating heat exchanger according to claim 1, wherein at least one spacing means each is arranged within each of said sectors.

11. A rotating heat exchanger according to claim 3, wherein said sheet-metal strips are combined into a comblike assembly at the base portion thereof provided with a plurality of teeth formed by said strips, at least one of said comb-like assembly being arranged within each of said sectors.

12. A rotating heat exchanger according to claim 1, further comprising roller means spaced around the periphery thereof for rotatably supporting thereon said disks, external ring means provided with external tooth means, individual disks being secured to said ring means, and at least one of said roller means being provided with tooth means engaging the teeth of said ring means for rotation of said roller means by said ring means.

13. A rotating heat exchanger according to claim 3, further comprising roller means distributed along the periphery of said disks for rotatably supporting thereon said disks, and means including said roller means to effect rotation of said disks.

References Cited in the file of this patent UNITED STATES PATENTS 1,560,271 Lynger Nov. 3, 1925 2,469,758 Alcock May 10, 1949 2,743,945 Bentele et al. May 1, 1956 2,911,197 Scherenberg Nov. 3, 1959 FOREIGN PATENTS 234,198 Great Britain May 28, 1925 

